Asymmetrically Routed Phased Arrays as an Enabler for Analog Directional Encoding

This paper introduces the concept of analog directional encoding as a new approach for delivering an encoded signal towards specific targets only while providing white noise to most of the other directions. The proposed method exploits the directional dependency of the group delay between each pair of adjacent antennas in series-fed asymmetrically routed phased arrays to generate “beams of correlation”, which have analogous behaviors of the power beam patterns in classical analogical beam-forming methods. This strategy allows two additional security layers to the communication, consisting in the necessary knowledge of the encoding scheme and of the steering direction of the transmitter in order to correctly decode the received message. Moreover, the received message can be compared with the sent message, if it is a priori known, to estimate the angle-of-arrival of the signal.